The invention relates to a pump having a cutting impeller and a pre-cutter driven by a shaft portion that axially projects from the cutting impeller.
A pump of this type is known from DE 10 2005 014 348 B3 and is used for example in machine tools for circulating lubricating coolant emulsions that are contaminated with metal chippings. This pump is a centrifugal pump that is additionally provided with an axial impeller disposed upstream of a radial impeller, said axial impeller being configured as a cutting impeller and having, at its upstream end, cutting edges that cooperate with stationary counter blades arranged radially in a suction passage, so that chippings and other contaminants that have been sucked in are cut-off and chopped. The pre-cutter serves for chopping coarse contaminants before they are sucked-in by the axial impeller and are then chopped further.